In-app purchases on test version before going live?

The instructions for submitting IAP say that you have to submit it with a new build. Is it possible for that build to be a TestFlight build? It doesn't make sense to me that an app would have to go live, then submit an update for that just to get IAP reviewed. Maybe I'm misunderstanding something, although Apple's doc's have been known to be inaccurate and/or misleading.

In other words, if I want to test IAP in TestFlight builds before the game is ever released live, will it work if I submit a build for review and use the manual release option, but never release that version?
Interestingly, I found that the products work in my local device build, so I will assume that they will also work in TestFlight builds. Still yet to find out for sure.
In-app purchases on test version before going live?
 
 
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